Hitherto various kinds of modeling compositions have been known and used particularly for children's play. For instance chlorinated paraffin blended with nitrile rubber; bentonite kneaded with oil; kneaded compounds of clay, japan wax or paraffin and castor oil; plastic modeling compositions comprising synthetic plastic material, etc. have been proposed. All of them, however, had some defect such as the following: viscosity is too variable depending on the environmental temperature; unsanitary because of oil oozability and strong offensive smell; too remarkable variation of hardness depending on the temperature; too high elasticity and lack in plasticity; and inferior releasability from molds used in modeling.
Recently some modeling compositions mainly composed of grain flour such as wheat flour have been proposed. Wheat flour is easily available at a low price and in great quantity and has no poison even when put into the mouth, and in wet condition shows very preferable plasticity and workability: therefore, the previous modeling compositions have now been substantially replaced by modeling compositions of grain flour.
As far as we know, the most conventional modeling composition of grain flour has been disclosed by Noah W. McVicker, et al. in U.S. Pat. No. 3,167,440, patented Jan. 26, 1965. That composition consisted essentially of a mixture formed from about 450 to 550 pounds of grain flour, about 450 to 550 pounds of water, about 1 to 3 gallons of kerosene and about 75 to 200 pounds of a water soluble substantially non-toxic inorganic chlorine salt selected from the group consisting of sodium chloride, sodium hypochlorite, sodium chlorite and potassium chloride; and if desired a small amount of hardening and astringent agent selected from complex aluminum salts, complex chromium salts and ferric salts; and a small amount of drying and preservative agent selected from a group consisting of borax, salicylic acid, sodium benzoate, sorbic acid, sodium and calcium propionate, calcium oxide, colemanite, rasorite and kernite.
The inventors of the present invention have also disclosed two improved modeling compositions of grain flour in Japanese Pat. Nos. 741581 (Publication No. 4317/1974) and 786306 (Publication No. 49571/1974). In the former a heat-treated wheat flour and a straight-chain hydrocarbon normal paraffin having from 10 to 20 carbon atoms are used in order to improve various properties of the composition, and in the latter a deliquescent salt such as magnesium chloride, aluminum chloride, etc., is added to prevent change of the quality of the composition. The product according to the above Japanese patents has almost perfect properties as a modeling composition for children's play and has been provided to the market in large quantity.
This kind of modeling composition, essentially composed of starch-bearing material such as grain flour, is used widely not only for children's play, but also for manufacturing craft works such as flowers and other handicraft articles. In order to be suitable for use in modeling handicraft articles, it is desirable that the composition have a rapid-drying property so as to harden relatively rapidly to a stiff condition, contrary to those for children's play: that is to say, the composition should be rather unreworkable. We previously found (see Japan Pat. No. 775271 [Publication No. 40656/1974]) that this object could be sufficiently attained by combining bread and synthetic latex with the known modeling composition mainly composed of grain flour, and a large quantity of this product has also been put on the market.